The field of invention is DIN rail latches for mounting components on a DIN rail, more particularly a dual mode DIN rail latch having tactile feedback.
A DIN rail being characterized by an elongate channel having opposed coplanar flanges along its length is used in the art for mounting electrical components in electrical panels. The rail is mounted in a panel using screws and the like. Components incorporating one or more DIN rail mounting latches are then detachably mounted to the rail.
Various latches have been developed for detachably mounting components to a DIN rail. A typical latch assembly has a lip integrally formed part of an electronic component chassis that engages an upper or lower flange of a DIN rail and a spring biased locking tab mounted to the chassis for slidable movement engages the opposing flange of the DIN rail. To mount the chassis on the DIN rail, the user hooks the lip over the upper DIN rail flange and then snaps the chassis in place by applying pressure to the chassis forcing it toward the DIN rail. To detach the chassis from the DIN rail, the user pries the locking tab downward disengaging the tab from the DIN rail lower flange allowing the chassis to swing away from the rail and disengage the lip from the upper flange.
Single mode latches have a locking tab that is continuously urged toward the DIN rail by springs. Large components, such as an Allen-Bradley MicroLogix.TM. 1000 programmable controller, available from Rockwell Automation/Allen-Bradley, Milwaukee, Wis., have two or more latches for mounting the controller to the DIN rail. In order to detach the MicroLogix.TM. 1000 controller from the DIN rail all the locking tabs must be pried downwardly. If the latches are the single mode type, all the tabs must be pulled away from the DIN rail and held in that position while swinging the controller away from the DIN rail. This is a difficult task for a user with only two hands. The task becomes even more difficult when multiple components are interlocked together, such as in a "tongue and groove" configuration, forming a long module assembly having multiple rail latches.
Dual mode latches have been developed to overcome this problem. These dual mode latches, such as described in Japanese Patent Application 1-75815, filed on Mar. 28, 1989 and laid open on Oct. 15, 1990 have a first mode (closed position), for mounting to the DIN rail, and a second mode (open position), for detaching from the DIN rail. In the first mode, the latch continuously urges the locking tab toward the DIN rail as in the single mode type. In the second mode, the locking tab is held away from the DIN rail using means, such as described in Japanese Patent Application 1-75815, thus freeing the user's hands to swing the mounted component away from the DIN rail.
In certain situations, a user may desire to pull the tab downwardly without switching from the first mode to the second mode. The present dual mode latches do not provide any indication of an impending mode change.